sys/kern/subr_scanf.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (c) 1990, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Chris Torek.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * From: Id: vfscanf.c,v 1.13 1998/09/25 12:20:27 obrien Exp
  35  * From: static char sccsid[] = "@(#)strtol.c   8.1 (Berkeley) 6/4/93";
  36  * From: static char sccsid[] = "@(#)strtoul.c  8.1 (Berkeley) 6/4/93";
  37  */
  38
  39 #include <sys/cdefs.h>
  40 __FBSDID("$FreeBSD$");
  41
  42 #include <sys/param.h>
  43 #include <sys/systm.h>
  44 #include <sys/ctype.h>
  45 #include <sys/limits.h>
  46
  47 /*
  48  * Note that stdarg.h and the ANSI style va_start macro is used for both
  49  * ANSI and traditional C compilers.
  50  */
  51 #include <machine/stdarg.h>
  52
  53 #define BUF             32      /* Maximum length of numeric string. */
  54
  55 /*
  56  * Flags used during conversion.
  57  */
  58 #define LONG            0x01    /* l: long or double */
  59 #define SHORT           0x04    /* h: short */
  60 #define SUPPRESS        0x08    /* suppress assignment */
  61 #define POINTER         0x10    /* weird %p pointer (`fake hex') */
  62 #define NOSKIP          0x20    /* do not skip blanks */
  63 #define QUAD            0x400
  64 #define SHORTSHORT      0x4000  /** hh: char */
  65
  66 /*
  67  * The following are used in numeric conversions only:
  68  * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
  69  * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
  70  */
  71 #define SIGNOK          0x40    /* +/- is (still) legal */
  72 #define NDIGITS         0x80    /* no digits detected */
  73
  74 #define DPTOK           0x100   /* (float) decimal point is still legal */
  75 #define EXPOK           0x200   /* (float) exponent (e+3, etc) still legal */
  76
  77 #define PFXOK           0x100   /* 0x prefix is (still) legal */
  78 #define NZDIGITS        0x200   /* no zero digits detected */
  79
  80 /*
  81  * Conversion types.
  82  */
  83 #define CT_CHAR         0       /* %c conversion */
  84 #define CT_CCL          1       /* %[...] conversion */
  85 #define CT_STRING       2       /* %s conversion */
  86 #define CT_INT          3       /* integer, i.e., strtoq or strtouq */
  87 typedef u_quad_t (*ccfntype)(const char *, char **, int);
  88
  89 static const u_char *__sccl(char *, const u_char *);
  90
  91 int
  92 sscanf(const char *ibuf, const char *fmt, ...)
  93 {
  94         va_list ap;
  95         int ret;
  96
  97         va_start(ap, fmt);
  98         ret = vsscanf(ibuf, fmt, ap);
  99         va_end(ap);
 100         return(ret);
 101 }
 102
 103 int
 104 vsscanf(const char *inp, char const *fmt0, va_list ap)
 105 {
 106         int inr;
 107         const u_char *fmt = (const u_char *)fmt0;
 108         int c;                  /* character from format, or conversion */
 109         size_t width;           /* field width, or 0 */
 110         char *p;                /* points into all kinds of strings */
 111         int n;                  /* handy integer */
 112         int flags;              /* flags as defined above */
 113         char *p0;               /* saves original value of p when necessary */
 114         int nassigned;          /* number of fields assigned */
 115         int nconversions;       /* number of conversions */
 116         int nread;              /* number of characters consumed from fp */
 117         int base;               /* base argument to strtoq/strtouq */
 118         ccfntype ccfn;          /* conversion function (strtoq/strtouq) */
 119         char ccltab[256];       /* character class table for %[...] */
 120         char buf[BUF];          /* buffer for numeric conversions */
 121
 122         /* `basefix' is used to avoid `if' tests in the integer scanner */
 123         static short basefix[17] =
 124                 { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };
 125
 126         inr = strlen(inp);
 127
 128         nassigned = 0;
 129         nconversions = 0;
 130         nread = 0;
 131         base = 0;               /* XXX just to keep gcc happy */
 132         ccfn = NULL;            /* XXX just to keep gcc happy */
 133         for (;;) {
 134                 c = *fmt++;
 135                 if (c == 0)
 136                         return (nassigned);
 137                 if (isspace(c)) {
 138                         while (inr > 0 && isspace(*inp))
 139                                 nread++, inr--, inp++;
 140                         continue;
 141                 }
 142                 if (c != '%')
 143                         goto literal;
 144                 width = 0;
 145                 flags = 0;
 146                 /*
 147                  * switch on the format.  continue if done;
 148                  * break once format type is derived.
 149                  */
 150 again:          c = *fmt++;
 151                 switch (c) {
 152                 case '%':
 153 literal:
 154                         if (inr <= 0)
 155                                 goto input_failure;
 156                         if (*inp != c)
 157                                 goto match_failure;
 158                         inr--, inp++;
 159                         nread++;
 160                         continue;
 161
 162                 case '*':
 163                         flags |= SUPPRESS;
 164                         goto again;
 165                 case 'l':
 166                         if (flags & LONG){
 167                                 flags &= ~LONG;
 168                                 flags |= QUAD;
 169                         } else {
 170                                 flags |= LONG;
 171                         }
 172                         goto again;
 173                 case 'q':
 174                         flags |= QUAD;
 175                         goto again;
 176                 case 'h':
 177                         if (flags & SHORT){
 178                                 flags &= ~SHORT;
 179                                 flags |= SHORTSHORT;
 180                         } else {
 181                                 flags |= SHORT;
 182                         }
 183                         goto again;
 184
 185                 case '0': case '1': case '2': case '3': case '4':
 186                 case '5': case '6': case '7': case '8': case '9':
 187                         width = width * 10 + c - '0';
 188                         goto again;
 189
 190                 /*
 191                  * Conversions.
 192                  *
 193                  */
 194                 case 'd':
 195                         c = CT_INT;
 196                         ccfn = (ccfntype)strtoq;
 197                         base = 10;
 198                         break;
 199
 200                 case 'i':
 201                         c = CT_INT;
 202                         ccfn = (ccfntype)strtoq;
 203                         base = 0;
 204                         break;
 205
 206                 case 'o':
 207                         c = CT_INT;
 208                         ccfn = strtouq;
 209                         base = 8;
 210                         break;
 211
 212                 case 'u':
 213                         c = CT_INT;
 214                         ccfn = strtouq;
 215                         base = 10;
 216                         break;
 217
 218                 case 'x':
 219                         flags |= PFXOK; /* enable 0x prefixing */
 220                         c = CT_INT;
 221                         ccfn = strtouq;
 222                         base = 16;
 223                         break;
 224
 225                 case 's':
 226                         c = CT_STRING;
 227                         break;
 228
 229                 case '[':
 230                         fmt = __sccl(ccltab, fmt);
 231                         flags |= NOSKIP;
 232                         c = CT_CCL;
 233                         break;
 234
 235                 case 'c':
 236                         flags |= NOSKIP;
 237                         c = CT_CHAR;
 238                         break;
 239
 240                 case 'p':       /* pointer format is like hex */
 241                         flags |= POINTER | PFXOK;
 242                         c = CT_INT;
 243                         ccfn = strtouq;
 244                         base = 16;
 245                         break;
 246
 247                 case 'n':
 248                         nconversions++;
 249                         if (flags & SUPPRESS)   /* ??? */
 250                                 continue;
 251                         if (flags & SHORTSHORT)
 252                                 *va_arg(ap, char *) = nread;
 253                         else if (flags & SHORT)
 254                                 *va_arg(ap, short *) = nread;
 255                         else if (flags & LONG)
 256                                 *va_arg(ap, long *) = nread;
 257                         else if (flags & QUAD)
 258                                 *va_arg(ap, quad_t *) = nread;
 259                         else
 260                                 *va_arg(ap, int *) = nread;
 261                         continue;
 262                 }
 263
 264                 /*
 265                  * We have a conversion that requires input.
 266                  */
 267                 if (inr <= 0)
 268                         goto input_failure;
 269
 270                 /*
 271                  * Consume leading white space, except for formats
 272                  * that suppress this.
 273                  */
 274                 if ((flags & NOSKIP) == 0) {
 275                         while (isspace(*inp)) {
 276                                 nread++;
 277                                 if (--inr > 0)
 278                                         inp++;
 279                                 else
 280                                         goto input_failure;
 281                         }
 282                         /*
 283                          * Note that there is at least one character in
 284                          * the buffer, so conversions that do not set NOSKIP
 285                          * can no longer result in an input failure.
 286                          */
 287                 }
 288
 289                 /*
 290                  * Do the conversion.
 291                  */
 292                 switch (c) {
 293
 294                 case CT_CHAR:
 295                         /* scan arbitrary characters (sets NOSKIP) */
 296                         if (width == 0)
 297                                 width = 1;
 298                         if (flags & SUPPRESS) {
 299                                 size_t sum = 0;
 300                                 for (;;) {
 301                                         if ((n = inr) < width) {
 302                                                 sum += n;
 303                                                 width -= n;
 304                                                 inp += n;
 305                                                 if (sum == 0)
 306                                                         goto input_failure;
 307                                                 break;
 308                                         } else {
 309                                                 sum += width;
 310                                                 inr -= width;
 311                                                 inp += width;
 312                                                 break;
 313                                         }
 314                                 }
 315                                 nread += sum;
 316                         } else {
 317                                 bcopy(inp, va_arg(ap, char *), width);
 318                                 inr -= width;
 319                                 inp += width;
 320                                 nread += width;
 321                                 nassigned++;
 322                         }
 323                         nconversions++;
 324                         break;
 325
 326                 case CT_CCL:
 327                         /* scan a (nonempty) character class (sets NOSKIP) */
 328                         if (width == 0)
 329                                 width = (size_t)~0;     /* `infinity' */
 330                         /* take only those things in the class */
 331                         if (flags & SUPPRESS) {
 332                                 n = 0;
 333                                 while (ccltab[(unsigned char)*inp]) {
 334                                         n++, inr--, inp++;
 335                                         if (--width == 0)
 336                                                 break;
 337                                         if (inr <= 0) {
 338                                                 if (n == 0)
 339                                                         goto input_failure;
 340                                                 break;
 341                                         }
 342                                 }
 343                                 if (n == 0)
 344                                         goto match_failure;
 345                         } else {
 346                                 p0 = p = va_arg(ap, char *);
 347                                 while (ccltab[(unsigned char)*inp]) {
 348                                         inr--;
 349                                         *p++ = *inp++;
 350                                         if (--width == 0)
 351                                                 break;
 352                                         if (inr <= 0) {
 353                                                 if (p == p0)
 354                                                         goto input_failure;
 355                                                 break;
 356                                         }
 357                                 }
 358                                 n = p - p0;
 359                                 if (n == 0)
 360                                         goto match_failure;
 361                                 *p = 0;
 362                                 nassigned++;
 363                         }
 364                         nread += n;
 365                         nconversions++;
 366                         break;
 367
 368                 case CT_STRING:
 369                         /* like CCL, but zero-length string OK, & no NOSKIP */
 370                         if (width == 0)
 371                                 width = (size_t)~0;
 372                         if (flags & SUPPRESS) {
 373                                 n = 0;
 374                                 while (!isspace(*inp)) {
 375                                         n++, inr--, inp++;
 376                                         if (--width == 0)
 377                                                 break;
 378                                         if (inr <= 0)
 379                                                 break;
 380                                 }
 381                                 nread += n;
 382                         } else {
 383                                 p0 = p = va_arg(ap, char *);
 384                                 while (!isspace(*inp)) {
 385                                         inr--;
 386                                         *p++ = *inp++;
 387                                         if (--width == 0)
 388                                                 break;
 389                                         if (inr <= 0)
 390                                                 break;
 391                                 }
 392                                 *p = 0;
 393                                 nread += p - p0;
 394                                 nassigned++;
 395                         }
 396                         nconversions++;
 397                         continue;
 398
 399                 case CT_INT:
 400                         /* scan an integer as if by strtoq/strtouq */
 401 #ifdef hardway
 402                         if (width == 0 || width > sizeof(buf) - 1)
 403                                 width = sizeof(buf) - 1;
 404 #else
 405                         /* size_t is unsigned, hence this optimisation */
 406                         if (--width > sizeof(buf) - 2)
 407                                 width = sizeof(buf) - 2;
 408                         width++;
 409 #endif
 410                         flags |= SIGNOK | NDIGITS | NZDIGITS;
 411                         for (p = buf; width; width--) {
 412                                 c = *inp;
 413                                 /*
 414                                  * Switch on the character; `goto ok'
 415                                  * if we accept it as a part of number.
 416                                  */
 417                                 switch (c) {
 418
 419                                 /*
 420                                  * The digit 0 is always legal, but is
 421                                  * special.  For %i conversions, if no
 422                                  * digits (zero or nonzero) have been
 423                                  * scanned (only signs), we will have
 424                                  * base==0.  In that case, we should set
 425                                  * it to 8 and enable 0x prefixing.
 426                                  * Also, if we have not scanned zero digits
 427                                  * before this, do not turn off prefixing
 428                                  * (someone else will turn it off if we
 429                                  * have scanned any nonzero digits).
 430                                  */
 431                                 case '0':
 432                                         if (base == 0) {
 433                                                 base = 8;
 434                                                 flags |= PFXOK;
 435                                         }
 436                                         if (flags & NZDIGITS)
 437                                             flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
 438                                         else
 439                                             flags &= ~(SIGNOK|PFXOK|NDIGITS);
 440                                         goto ok;
 441
 442                                 /* 1 through 7 always legal */
 443                                 case '1': case '2': case '3':
 444                                 case '4': case '5': case '6': case '7':
 445                                         base = basefix[base];
 446                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 447                                         goto ok;
 448
 449                                 /* digits 8 and 9 ok iff decimal or hex */
 450                                 case '8': case '9':
 451                                         base = basefix[base];
 452                                         if (base <= 8)
 453                                                 break;  /* not legal here */
 454                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 455                                         goto ok;
 456
 457                                 /* letters ok iff hex */
 458                                 case 'A': case 'B': case 'C':
 459                                 case 'D': case 'E': case 'F':
 460                                 case 'a': case 'b': case 'c':
 461                                 case 'd': case 'e': case 'f':
 462                                         /* no need to fix base here */
 463                                         if (base <= 10)
 464                                                 break;  /* not legal here */
 465                                         flags &= ~(SIGNOK | PFXOK | NDIGITS);
 466                                         goto ok;
 467
 468                                 /* sign ok only as first character */
 469                                 case '+': case '-':
 470                                         if (flags & SIGNOK) {
 471                                                 flags &= ~SIGNOK;
 472                                                 goto ok;
 473                                         }
 474                                         break;
 475
 476                                 /* x ok iff flag still set & 2nd char */
 477                                 case 'x': case 'X':
 478                                         if (flags & PFXOK && p == buf + 1) {
 479                                                 base = 16;      /* if %i */
 480                                                 flags &= ~PFXOK;
 481                                                 goto ok;
 482                                         }
 483                                         break;
 484                                 }
 485
 486                                 /*
 487                                  * If we got here, c is not a legal character
 488                                  * for a number.  Stop accumulating digits.
 489                                  */
 490                                 break;
 491                 ok:
 492                                 /*
 493                                  * c is legal: store it and look at the next.
 494                                  */
 495                                 *p++ = c;
 496                                 if (--inr > 0)
 497                                         inp++;
 498                                 else
 499                                         break;          /* end of input */
 500                         }
 501                         /*
 502                          * If we had only a sign, it is no good; push
 503                          * back the sign.  If the number ends in `x',
 504                          * it was [sign] '0' 'x', so push back the x
 505                          * and treat it as [sign] '0'.
 506                          */
 507                         if (flags & NDIGITS) {
 508                                 if (p > buf) {
 509                                         inp--;
 510                                         inr++;
 511                                 }
 512                                 goto match_failure;
 513                         }
 514                         c = ((u_char *)p)[-1];
 515                         if (c == 'x' || c == 'X') {
 516                                 --p;
 517                                 inp--;
 518                                 inr++;
 519                         }
 520                         if ((flags & SUPPRESS) == 0) {
 521                                 u_quad_t res;
 522
 523                                 *p = 0;
 524                                 res = (*ccfn)(buf, (char **)NULL, base);
 525                                 if (flags & POINTER)
 526                                         *va_arg(ap, void **) =
 527                                                 (void *)(uintptr_t)res;
 528                                 else if (flags & SHORTSHORT)
 529                                         *va_arg(ap, char *) = res;
 530                                 else if (flags & SHORT)
 531                                         *va_arg(ap, short *) = res;
 532                                 else if (flags & LONG)
 533                                         *va_arg(ap, long *) = res;
 534                                 else if (flags & QUAD)
 535                                         *va_arg(ap, quad_t *) = res;
 536                                 else
 537                                         *va_arg(ap, int *) = res;
 538                                 nassigned++;
 539                         }
 540                         nread += p - buf;
 541                         nconversions++;
 542                         break;
 543
 544                 }
 545         }
 546 input_failure:
 547         return (nconversions != 0 ? nassigned : -1);
 548 match_failure:
 549         return (nassigned);
 550 }
 551
 552 /*
 553  * Fill in the given table from the scanset at the given format
 554  * (just after `[').  Return a pointer to the character past the
 555  * closing `]'.  The table has a 1 wherever characters should be
 556  * considered part of the scanset.
 557  */
 558 static const u_char *
 559 __sccl(char *tab, const u_char *fmt)
 560 {
 561         int c, n, v;
 562
 563         /* first `clear' the whole table */
 564         c = *fmt++;             /* first char hat => negated scanset */
 565         if (c == '^') {
 566                 v = 1;          /* default => accept */
 567                 c = *fmt++;     /* get new first char */
 568         } else
 569                 v = 0;          /* default => reject */
 570
 571         /* XXX: Will not work if sizeof(tab*) > sizeof(char) */
 572         for (n = 0; n < 256; n++)
 573                      tab[n] = v;        /* memset(tab, v, 256) */
 574
 575         if (c == 0)
 576                 return (fmt - 1);/* format ended before closing ] */
 577
 578         /*
 579          * Now set the entries corresponding to the actual scanset
 580          * to the opposite of the above.
 581          *
 582          * The first character may be ']' (or '-') without being special;
 583          * the last character may be '-'.
 584          */
 585         v = 1 - v;
 586         for (;;) {
 587                 tab[c] = v;             /* take character c */
 588 doswitch:
 589                 n = *fmt++;             /* and examine the next */
 590                 switch (n) {
 591
 592                 case 0:                 /* format ended too soon */
 593                         return (fmt - 1);
 594
 595                 case '-':
 596                         /*
 597                          * A scanset of the form
 598                          *      [01+-]
 599                          * is defined as `the digit 0, the digit 1,
 600                          * the character +, the character -', but
 601                          * the effect of a scanset such as
 602                          *      [a-zA-Z0-9]
 603                          * is implementation defined.  The V7 Unix
 604                          * scanf treats `a-z' as `the letters a through
 605                          * z', but treats `a-a' as `the letter a, the
 606                          * character -, and the letter a'.
 607                          *
 608                          * For compatibility, the `-' is not considered
 609                          * to define a range if the character following
 610                          * it is either a close bracket (required by ANSI)
 611                          * or is not numerically greater than the character
 612                          * we just stored in the table (c).
 613                          */
 614                         n = *fmt;
 615                         if (n == ']' || n < c) {
 616                                 c = '-';
 617                                 break;  /* resume the for(;;) */
 618                         }
 619                         fmt++;
 620                         /* fill in the range */
 621                         do {
 622                             tab[++c] = v;
 623                         } while (c < n);
 624                         c = n;
 625                         /*
 626                          * Alas, the V7 Unix scanf also treats formats
 627                          * such as [a-c-e] as `the letters a through e'.
 628                          * This too is permitted by the standard....
 629                          */
 630                         goto doswitch;
 631                         break;
 632
 633                 case ']':               /* end of scanset */
 634                         return (fmt);
 635
 636                 default:                /* just another character */
 637                         c = n;
 638                         break;
 639                 }
 640         }
 641         /* NOTREACHED */
 642 }
 643